Closure for an Easy Opening Container and a Container Provided with Such Closure

ABSTRACT

The present invention relates to a closure ( 1 ) for an easy opening container comprising a support and a foil ( 3 ) adhered to the support, which foil is provided with a tab ( 4 ) folded on to the foil, wherein the foil comprises a central concave section ( 5 ) and at least a flat section ( 6 ) beneath the tab, where optionally the tab is adhered to the flat section, and to a container comprising such closure.

The present invention relates to a closure for an easy opening containerand to a container provided with such closure.

Easy opening closures are used for closing an opening of a containerwith a foil, such that relatively easy by removing the foil the contentof the container will become available to the consumer. The foil isgenerally relatively vulnerable and is released from its containersupport by gripping a tab, which is connected to or integral with thefoil. Lifting the tap and exerting relatively low force will result in adetachment of the foil from the container support. After filling andclosing the container with the easy opening foil, the foil is protectedby a cap which overdoses the foil and is connected to the container. Inuse, the user first removes the protective cap and subsequently the foilby gripping the tap and peeling off the foil.

Such easy opening containers are also used for goods, such as food, thatare to be subjected to a heat treatment after closing the container.Generally, the tab is adhered to the foil and thereafter the foil isprovided with the desired shape and form. This may negatively influencethe adherence of the tab to the foil.

Over pressure build up in the container during heat treatment, forinstance a sterilization process will result in an outward bulging ofthe easy opening foil, even outside the confinement of the container.This may result in damage of the foil and/or damage to the tap.Eventually, this may result in a failure of the foil or that the tap isno longer available for opening the container by peeling of the foil.

This risk for damage to foil and/or tap of an easy opening container isrelatively high, when such easy opening containers are subjected to aheating treatment during which the containers are transported throughthe heat treatment apparatus, such as a retort apparatus, followingconveyors and/or guiding rails.

The present invention has for its object to provide a closure and acontainer provided with an easy opening foil which have a substantiallyreduced risk for damage of the foil and/or the tap during and after aheat treatment.

Accordingly, the present invention provides a closure for an easyopening container comprising a support and a foil adhered to thesupport, which foil is provided with a tab folded on to the foil,wherein the foil comprises a central concave section and at least a flatsection beneath the tab. The tab is thus first adhered to the flat foilsection underneath. Then the foil is shaped and provided with theconcave form leaving undisturbed the flat foil section during theforming process (no shearing of the glue during the forming) In thismanner, the tab will stay better attached to the foil and subsequentlyduring all the steps of the use of this end (during heat treatment,conveyors, rails, handling) and the chance to have the tab damaged willbe reduced. Obviously, the flat section can have different forms likeannular and exocentric flat section.

Due to the presence of a central concave section (extending inwardly ofthe container) and a flat foil section beneath the tab, the foil and thetab will move outwardly to such extent, that it can extend beyond theconfinement. Dependant on the diameter of the container, it could bulgedout up to about 20 mm on a large diameter. Preferably, the tab and foilsubstantially do not extend beyond (the confinement of the closure. Inother words, foil and tab do not extend outside the confinement of theclosure and therefore is the risk of sticking or hooking to parts of theapparatus substantially avoided. The concave section will bulgeoutwardly and when in contact with the tab, the tab will follow theoutward movement of the foil. However, due to the presence of the flatsection beneath the tab, this part of the foil will move to a lesserextent outwardly and thereby avoids the tab of projecting beyond theconfinement of the closure.

According to a preferred embodiment, the tap is folded onto the concavesection. This will increase the distance of the tap to the confinementof the closure and therefore further reduces a risk of projecting beyondthe confinement of the closure.

The outward bulging of the concave section is further reduced, and themaking of the foil is further simplified if, according to anotherpreferred embodiment of the invention, the flat section extends over thecircumference of the support. The outward movement of the concavesection is further reduced at the same relative overpressure when theflat section extends radially inwardly over and beyond the support. Thatis, the width of the flat section is larger than the support to whichthe foil is adhered. Practically it is preferred that the flat sectionextends over a length L of about 1-15 mm, such as 2-12 mm, in particular3-10 mm over and beyond the support.

In order to further reduce undesired lifting and extension of the tabbeyond the confinement, it is further preferred that the tab is adheredto the foil via the flat section. According to a preferred embodiment,the tab is adhered to the foil by adhesive. This has the advantage thatthe adhesive is applied and present on the flat section and the tab willremain at this location undisturbed when thereafter the concave centralsection is formed in the foil. Adhesive will not be transported to theoutside of the space between the flat section and the overlaying tap,because this part of the foil is not disturbed when forming the centralconcave section. According to another alternative embodiment the tab isadhered to the foil by mechanical structure. This means that the flatsection and the tap are entangled which resists separation of the tabfrom the flat section. Obviously, such mechanical structure ispreferably formed and applied in a flat section of an undisturbed partof the foil.

Preferably the free end of the tab does not contact the foil therebyproviding an elegant finger access.

The construction of the closure according to the invention is such thatat a pressure build up of about 0.1-2.5 bar the tab and foil remainwithin the confinement of the support.

The present invention is applicable for easy opening foils independentof the form of the support to which the foil is adhered. According to apreferred embodiment this support is part of a ring which is to beconnected to a container body.

Accordingly, the foil can be adhered to a ring support. Subsequently,the ring with the adhered foil is applied to a container body afterfilling the container body via the same opening. It is also possible,that the support is not present in a separate ring, but is formed at thefree end or in the wall of the container body. It is then possible thatthe container is first filled and subsequently the foil applied, or thatthe container after application of the foil is filled from the otheropen container body end.

A foil to be used in relation to the present invention may be made ofany suitable material which may be characterized as a foil, because ithas a thickness of about 0.02 to 1.0 mm, preferably 0.05 to 0.5 mm. Thefoil may be provided with a surface structure or be imprinted. Thematerial of the foil may be metal, such as aluminium, or plastic, suchas polypropylene, or may have the form of a metal foil provided with aplastic laminate. A further aspect of the present invention relates to acontainer provided with a closure as defined and characterized hereinbefore.

Mentioned and other features and characteristics of the closure andcontainer of the present invention will be further illustrated withreference to particular embodiments which are given for illustrativepurposes without any intention for limitation of the present invention.In that respect reference will be made to drawings, wherein:

FIG. 1: a prospective view of an easy opening closure according to theinvention;

FIG. 2: a top view of the closure of FIG. 1;

FIG. 3: a side view of the closure of FIG. 1;

FIG. 4: a cross-section of the closure of FIG. 1;

FIG. 4A: the closure in the overpressure status;

FIG. 5: at a larger scale a cross-section over the line V-V in FIG. 2;

FIG. 6: at a larger scale a cross-section over the line IV-IV in FIG. 2;

FIG. 7: a cross-section corresponding to FIG. 5 showing the bulging orfoil and tap due to over pressure;

FIG. 8: another embodiment of the closure according to the presentinvention;

FIG. 8A: a cross-section similar to FIG. 5 of the closure of FIG. 8; and

FIG. 9: shows a perspective view of another closure according to theinvention.

FIG. 1 shows a closure 1 according to the invention. The closure 1comprises a ring 2 to which is adhered a foil 3. The foil 3 comprises atab 4 which is integral with the foil 3 and is folded over and onto thefoil 3. The foil further comprises a central concave section 5surrounded by an annular flat section 6.

FIG. 2 shows that the tab 4 has a folded part 7 connected to anintermediate tab part 8 and a free end tab part 9. The intermediate tabpart 8 extends over the annular flat section 6 and the fee end tab part9 extends over the central concave section and is folded towards thissection by a fold line 10.

FIG. 3 shows in side view the closure 1 according to the invention withthe central concave section 5 extending beneath the lower confinement 11of the closure 1. A similar view is given in the cross-section accordingto FIG. 4.

FIG. 5 shows more in detail the closure 1 according to the invention.The ring 2 comprises an outer curl 12 which may be seamed onto a body ofa container (not shown). The ring has a flat ring support 13 connectedto the curl 12 via a ring wall 14. The flat ring support 13 ends in acurl 15 of which the curl end 16 faces the ring support 13. The foil 3at the flat section 6 is adhered to the ring support 13 using adhesive17. In stead of adhesive, heat sealing may be used in the alternative.The tab 4 with its intermediate tab part 8 is adhered to the foil 6using adhesive 18. It is noted that the flat section 6 has a very largeangle due to the slanted position of the flat ring support 13. The tab 4follows the form of the foil 3 because the structuring of the foil 3takes place after the bending over and adherence with adhesive 18 of thetab 4 to the foil 6.

FIG. 6 shows the adherence of the foil 3 with its flat section 6 to thering support 13 using adhesive 17.

FIG. 4A and 7 show the shape of the foil 3 and the tab 4 when pressurebuild up occurs in a container provided with a closure 1 according tothe invention. It is shows that the foil 3 bulges outwardly andtransformed the concave section into a convex section and that with thistransformation also moved the tab 4. However, the foil 3 and inparticular the free end 9 of the tab 4 remained within the confinement19 of the closure 1. At larger diameter the free end 9 and the tab 4 mayextend beyond the confinement as well, if so desired.

FIGS. 8 and 8A show another closure 20 according to the invention. Acontainer body 21 is provided with a support 22 ending in a curl 23which is counter clockwise curled such that the curl end 24 faces thecurl 23. A curl gap 25 is closed off by the foil 26 which is adhered tothe curl 23 and to the support 22 by adhesive 27 (heat sealing may alsobe used).

According to the invention, the foil 26 is provided with an annular flatsection 28 extending over a length L of about 6 mm beyond the support 22and the curl 23. The foil 26 is further provided with a concave centralsection 29. The tab 38 which is integral with the foil 26 is folded overthe flat section 28 and connected thereto using adhesive 27. The tab 38is further comprising a free tab end 30 which is folded along theconcave foil section 29. After having been subjected to a heat treatmentand after balancing the internal pressure again by cooling, the free end30 will have slightly separated from the concave central section 29thereby providing a finger access 31.

FIG. 9 shows a closure 32 according to the invention. The closure 32comprises a ring 33. The foil 34 is adhered to a non-shown ring supportusing adhesive. The foil 34 comprises an integral tab 35 which is foldedover and on the foil 34.

The foil 34 comprises a flat foil section 36 extending beneath andlateral of the tab 35. This implies that the concave central foilsection 37 extends almost over the entire circumference except for theflat foil section 36. Still, this closure with the foil and tapaccording to the invention and remain within the confinement of the ring33 during over pressure build up in the container to which the closure32 connected to.

1. A closure for an easy opening container comprising a support and afoil adhered to the support, which foil is provided with a tab folded onto the foil, wherein the foil comprises a central concave section and atleast a flat section beneath the tab, where optionally the tab isadhered to the flat section.
 2. The closure according to claim 1,wherein the tab is folded on to the concave section.
 3. The closureaccording to claim 1, wherein the fiat section extends over thecircumference of the support.
 4. The closure according to claim 1,wherein the flat section extends radially inwardly over and beyond thesupport.
 5. The closure according to claim 4, wherein the flat sectionextends over a length L of about 1-15 mm, such as 2-12 mm, in particular3-10 mm, over and beyond the support.
 6. The closure according to claim1, wherein the tab is adhered to the foil via the flat section.
 7. Theclosure according to claim 6, wherein the tab is adhered to the foil byan adhesive.
 8. The closure according to claim 6, wherein the tab isadhered to the foil by a mechanical structure.
 9. The closure accordingto claim 1, wherein the free end of the tab provides for finger access.10. The closure according to claim 1, wherein after pressure build up inthe container, the tab remains attached to the foil within theconfinement of the support.
 11. The closure according to claim 1,wherein the support is a ring to be connected to a container body. 12.The closure according to claim 1, made of metal, plastic, or plasticlaminated metal.
 13. A container provided with a closure according toclaim 1.